Treatment of cellulosic fabrics and the fabrics obtained



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3,081,144 TREATMENT OF CELLULOSIC FABRICS AND THE FABRICS OBTAINED JohnLeslie Gardon, Levittown, and Leo S. Luskin, Philadelphia, Pa.,assignors to Rohm & Haas Company, Philadelphia, Pa., a corporation ofDelaware N Drawing. Filed Oct. 10, 1960, Ser. No. 61,374 8 Claims. (Cl.8-116) This invention relates to the treatment of cellulosic fabrics,such as those of cotton and regenerated cellulose rayon, for the purposeof imparting to them increased resilience, improved recovery fromcreasing, wrinkling, and other deformations, and the characteristic ofhaving reduced shrinkage on washing so that partial or completedimensional stabilization may be effected. The invention also embracesthe treated fabrics obtained.

In accordance with the present invention, it has been found thatcellulosic fabrics, woven, knitted, or otherwise formed, have reducedshrinkage on washing and acquire resistance to creasing and crushingwhen they are treated with a carbinol selected from the group consistingof 2,5- furandimethanol and furfuryl alcohol or by a mixture thereof.The former of these compounds has the formula Both of these compoundsmay be called furancarbinols and have the generic formula H0CHz 0(CH2O)n-i H (m) wherein n is an integer having a value of 1 to 2.

While both of these carbinols serve to improve the crease resistance ofcellulosic fabrics, the 2,5-furandimethanol is the more efiicient of thetwo. That these compounds could serve in this capacity is quitesurprising since closely related compounds, such as the tetrahydro-2,5-furandimethanol, are incapable of creaseproofing cellulose fabrics.The extent of modification by means of these carbinols may be controlledby variation in the proportion of the carbinol and by variation in theamount of catalyst employed during the treatment therewith.

The treatment with the carbinol may be effected most advantageously bymeans of aqueous solutions thereof in which the carbinol is dissolved ata concentration which may vary from 2 to 25% by weight. Preferably, theconcentration is from 5 to 15% to obtain the maximum benefits in creaseproofing and the like.

Thet reatment with the carbinol is carried out in the presence of acatalyst. Suitable catalysts are acids or acidic salts, such as citricacid, oxalic acid, potassium persulfate, potassium bisulfate, magnesiumchloride, ammonium chloride, zinc nitrate, zinc fluoborate, zincperchlorate, boron trifluoride complexes, such as the phenol complex ofborontrifiuoride, and amine salts, such as the hydrochloride or sulfateof triethylamine, pyridine, morpholine, and Z-methyI-Z-aminopropanol-1.Citric acid is a preferred catalyst with relatively little tendency tocause discoloration requiring bleaching. One of the outstandingadvantages of the carbinols is the fact that they need only mildlyacidic catalysts making it possible to accomplish the creaseproofingtreatment with a minimum loss of tensile strength in the fabric beingtreated.

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Conveniently, the amount of catalyst may vary from about 0.1 to 5% andis preferably in the range of 2% to 4% concentration in the aqueoussolution of the carbinol.

The catalyzed solution of the carbinol is compatible with solutions ordispersions of most of the common textile finishing agents, such assynethic polymer latices and aminoplast resins or precondensates, sothat they may be applied with the carbinol to produce changes in thehand or other properties of the fabric.

The aqueous solution containing the carbinol and catalyst may be appliedto the fabric in any suitable manner such as spraying or impregnation.In general, it is preferable to use some method of impregnation. Withpiece goods, this is conveniently carried out with the various machinesused for treating fabrics in open width, such as pads or jigs. However,it is not required that the impregnation be carried out in open width,and the fabric may be handled in any form. In treating garments or otherarticles made from cellulosic fabrics, the impregnation may be carriedout in a tumble wheel, laundry machine, or other suitable equipment.After application of the solution, it is desirable to remove the excesssolution by squeezing the fabric between rollers, or by shaking orcentrifuging it, in order to insure a more even treatment. The fabrictreated with solution may be dried, such as by air-drying at normal roomtemperature or by heating in a drying oven at temperatures of 60 C. andup. The drying and curing operations are preferably done with the fabricopen and flat, so that it will have a smooth and even appearance whenfinished. In a preferred embodiment, the impregnated fabric, immediatelyafter impregnation and without preliminary low-temperature drying, iscarried in open width by a tenter frame through a curing oven where itis subjected to temperatures of about C. to about 200 C. or higher for aperiod of time ranging from about one-half minute to about one-half houror more, the shorter period being employed at the higher temperature andvice versa. Entirely satisfactory results are obtained by heating for 3to 5 minutes at about C. This curing operation not only dries theimpregnated fabric but apparently causes a reaction between the carbinoland the hydroxyl groups of the cellulose. The precise reaction is notknown. The treatment generally increases the weight of the fabric, theincrease in weight, or add-on of reagent, being from about 1% to 15% ormore, as desired, and for optimum results usually being 5% to 13%. It isnot intended, however, that the present invention be limited to thistheory of operation.

The treated fabrics exhibit a high degree of crush resistance and creaserecovery with little or no change in the hand or feel of the fabric. Inaddition, the treated fabrics have the important advantage that they donot retain chlorine, so that the use of bleaching agents containingchlorine does not cause deterioration either by way of discoloration orloss in tensile strength even when the treated fabrics which have beenbleached are subjected to ironing temperatures. The treated fabrics arealso resistant to shrinkage during laundering, and the treatment is verypermanent towards laundering, drycleaning, and other procedures forcleaning textile fabrics. The treatment of the present invention usingthe carbinol as the sole cross-linking or crease-proofing agent providesa finish that is more stable to hydrolysis in acids and alkalies thanthe usual nitrogenous or amin0- plast finishes. Any color introduced bythe treatment is readily removable by the usual bleaching agents, suchas sodium hypochlorite.

The following examples illustrate the present invention, and the partsand percentages therein are by weight unless otherwise noted. Thecrease-recovery values given below were determined by the ShirleyInstitute stator-t that;

3 procedure (British Standards Handbook No. 11, 1949 ed., page 128) inthe warp direction.

EXAMPLE A Preparation of 2,5-Furandimethanl S-hydroxymethylfurfural (63g., 0.5 mole) was dissolved in 25 ml. of water and was slowly added to95 g. (0.8 mole) of 33.3% aqueous sodium hydroxide. The reactiontemperature maintained itself at 30-32 C. After stirring two hours, themixture was saturated with carbon dioxide, cooling as needed. Filtrationgave 88 g. of a dark solid which was extracted with 100 ml. of ethylacetate. The aqueous filtrate was then extracted with the ethyl acetatein a continuous extraction at 50 C. for 48 hours. Evaporation gave 20 g.of a tan solid, and further extraction gave no more. The crude prodnotwas recrystallized from 40 ml. of 1,2-dimethoxyethane, giving 15 g. ofyellow crystals, M.P. 7879 C. The compound is very soluble in water,soluble in mineral oil, but insoluble in chlorinated solvents.

Analysis.Calcd. for C H O percent C, 56.24; percent H, 6.29. Found:percent C, 56.33; percent H, 6.40.

EXAMPLE 1 The carb'inol-treated fabric, which was 9.3% heavier after thetreatment than before, was insoluble in cupram monium hydroxide whilethe control dissolved readily.

The durability of the treatment was shown by the following tests.Samples of the furfuryl alcohol-treated fabric were extracted (1) inboiling water for one hour, (2) in 0.1 N HCl at 80 C. for one hour, and(3) in 0.1 NaOH for 24 hour-s at 20 C. The extracted samples were stillinsoluble in cuprammonium hydroxide and still had good crease-recovery.

EXAMPLE 2 (a) A sample of cotton print cloth was saturated with anaqueous solution containing of 2,5-furandimethanol and 1.5% of zincfluoborate. It was then put into an oven at 150 C. and baked for 15minutes. A control treated with water was similarly prepared. Afterbeing conditioned, the samples had the following creaserecovery values:

Crease-recovery angle, degrees Water control 71 2,5-furandimethanol 133The carbinol-treated fabric was 12.2% heavier than the initial fabric.

(b) The procedure of part (a) was repeated using rayon challis insteadof cotton printclo-th. The treated fabric was insoluble in cuprammoniumhydroxide and had similar crease-recovery.

(c) A solution containing 15% of 2,5-furandimethanol and 3.8% of citricacid was applied to cotton printcloth and the treated fabric was bakedfor 3.5 minutes 4 at 150 C. I-ts crease-recovery was improved by thistreatment from 71 to 124.

EXAMPLE 3 A sample of cotton pr-intcloth was saturated with a 15 aqueoussolution of 2,5 furandimethanol containing 0.5% NH Cl as the catalyst.It was cured in an oven at 150 C. for 3.5 minutes. After beingconditloned, the sample had a crease-recovery angle of 139.

EXAMPLE 4 A sample of cotton printcloth was treated with a so lu-tioncontaining 10% of furfuryl alcohol, 1% of oxalic acid, and 4% of apartially condensed urea-formaldehyde resin. The treated fabric wascured for 10 minutes at 150 C. After being conditioned, it had astiffer, firmer, more resilient hand and a crease-recovery of 137.

EXAMPLE 5 A sample of cotton printcloth was treated with a solutioncontaining a mixture of 10% 2,5-furandimethanol and 5%dimethylol-N,N'-ethyleneurea with 4% citric acid as a catalyst. Theapplication was made on a textile pad and the impregnated fabric wasbaked for 10 minutes at 150 C. After the fabric was conditioned, ltScrease-recovery angle was 139.

We claim:

1. The process comprising impregnating a cellulose fabric with anaqueous solution containing at least 2% by weight of at least onecarbinol selected from the group consisting of 2,5-furandimethanol andfurfuryl alcohol and at least about 0.1% by weight of an acidic catalystand heating the impregnated fabric at a temperature of about to 200 C.for at least a period of half a minute to half an hour, whereby thecrease resistance of the fabric is increased.

2. A process as defined in claim 1 in which the fabric 1s cotton. 3. Aprocess as defined in claim 1 in which the fabric is rayon.

4. A cellulose fabric having improved crease resistance obtained by theprocess of claim 1.

5. A cotton fabric having improved crease resistance obtained by theprocess of claim 1.

6. The process comprising impregnating a cellulose fabric with anaqueous solution containing 2 to 25 by welght of at least one carbinolselected from the group consisting of 2,5-furandimethanol and furfurylalcohol and 0.1 to 5% of an acidic catalyst and heating the impregnatedfabric at a temperature of about 110 to 200 C. for at least a period ofhalf a minute to half an hour.

7. The process comprising impregnating a cellulose fabric w1th anaqueous solution containing 2 to 25 by weight of 2,5-furandimethanol and0.1 to 5% of citric acid as a catalyst, and heating the impregnatedfabric at a temperature of about 110 to 200 C. for at least a period ofhalf a minute to half an hour.

8. The process comprising impregnating a cellulose fabric with anaqueous solution containing 2 to 25 by weight of furfuryl alcohol and0.1 to 5% of phenolborontrifiuoride complex as a catalyst, and heatingthe impregnated fabric at a temperature of about 110 to 200 C. for atleast a period of half a minute to half an hour.

References Cited in the file of this patent UNITED STATES PATENTS2,993,915 Luskin July 25, 1961

1. THE PROCESS COMPRISING IMPREGNATING A CELLULOSE FABRIC WITH ANAQUEOUS SOLUTION CONTAINING AT LEAST 2% BY WEIGHT OF AT LEAST ONECARBINOL SELECTED FROM THE GROUP CONSISTING OF 2, 5-FURANDIMETHANOL ANDFURFURYL ALCOHOL AND AT LEAST ABOUT 1.0% BY WEIGHT OF AN ACIDIC CATALYSTAND HEALING THE IMPREGNATED FABRIC AT A TEMPERATURE OF ABOUT 110* TO200* C. FOR AT LEAST A PERIOD OF HALF A MINUTE TO HALF AN HOUR, WHEREBYTHE CREASE RESISTANCE OF THE FABRIC IS INCREASED.